This invention relates to the continuous casting of ferrous alloy tubes, particularly cast iron pipes having thin walls relative to their diameters. More specifically, this invention pertains to the continuous vertical casting of an iron pipe using a tubular die and a heated coaxial core forming, with the die, an annular casting section.
A continuous casting installation for iron pipes with a small thickness/diameter ratio, using a tubular die and a heated coaxial core is described in U.S. Pat. No. 4,236,571. This patent pertains to a descending vertical continuous casting, with the molten iron entering the annular space between the die and the core from above.
Due to the narrowness of the annular passage for the molten iron, the risk of obstruction of the passage by prematurely solidified cast iron in contact with the wall of the tubular die, which is cooled externally by water, is high if the solid-liquid interface, i.e. the limit between the liquid and the solid phases of the cast iron, is not properly controlled. The object of the '501 patent was to define this solid-liquid interface as well as the means of externally cooling the tubular die in order to control this interface, especially at the beginning of the casting.